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<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>确保新的窗口没有获得焦点</title>
</head>

<body>
    <input type="button" value="打开窗口" onclick="open_win()">
    <script>
        function open_win() {
            window.open("https://c.runoob.com/");
            window.open("http://www.runoob.com/");
        }
    </script>
</body>

</html>